In motor vehicles today such filling level sensors are used, for example, to determine a filling level of fuel in a fuel container, and are known from practice. Here, the mounting arm is fabricated in two parts with a bracket fabricated from plastic and a lever wire for holding a float. The regulator is designed, for example, as a potentiometer with a sliding track which is arranged on the carrier part, or as a magnetically active position sensor having a resistor network which is arranged on the carrier part. The actuator of the regulator is usually attached to the bracket and, depending on the shape of the regulator, either has a sliding contact or a magnet. In order to ensure a constant prestress of the actuator or a constant distance between the actuator and the regulator components arranged on the carrier part, the mounting arm has two axial guides. As a result, forces transmitted from the float to the mounting arm are supported by the axial guides.
A disadvantage with the known filling level sensor is that it is of structurally very complex design as a result of the axial guides. In addition, because of the tolerances of the guides and of the mounting arm, in the known filling level sensor, the prestress of the actuator or the distance of the actuator can be kept constant only inadequately. As a result of forces acting on the mounting arm via the float, the mounting arm can tilt between the two guides so that the prestress of the actuator or the distance between the actuator and the components arranged on the carrier part is also changed.